Inductive coupler

Abstract

An inductive coupler (1) comprises a rectifier (2) to rectify an input alternating current power supply, a high frequency oscillator (3) driven by the rectified power supply, a modulator (4) to modulate the output of the high frequency oscillator (3) with a lower frequency alternating signal, a split transformer (6) having physically separable primary and secondary sections, and a demodulator (7). The output of the modulator (4) is coupled to the primary section of the transformer (6), and the secondary section of the transformer (6) is coupled to the demodulator (7) which demodulates the modulated high frequency signal to produce a low frequency power output. An auxiliary connector (8) connects a reference from the low frequency modulation signal imposed by the modulator (4) to the demodulator (7) to maintain synchronism.

We claim: 
     
       1. An inductive coupler comprising: a rectifier having an input and an output, said rectifier comprising a means for rectifying an alternating current power supply applied to said input to produce a rectified power supply at said output;   a high frequency oscillator, said high frequency oscillator having a power input and a high frequency signal output, said power input of said high frequency oscillator being operatively connected to an driven by, said output of said rectifier;   a modulator, said modulator having an input and an output, said input of said modulator being operatively connected to said high frequency signal output of said high frequency oscillator, said modulator comprising a means for modulating said high frequency signal output from said high frequency oscillator with a lower frequency alternating signal;   a split transformer means, said split transformer means having a primary and secondary section, said primary and secondary sections of said split transformer means comprising a means for rendering said sections physically separable, said output of said modulator being coupled to said primary section of said split transformer means;   a demodulator, said demodulator having an input and an output, said input of said demodulator being operatively coupled to said secondary section of said split transformer means, said demodulator comprising a means for demodulating a high frequency signal applied to said demodulator input from said secondary section of said split transformer means and for producing at said demodulator output a low frequency alternating current power output; and,   an auxiliary connector, said auxiliary connector having a first part operatively connected to a reference from said lower frequency alternating modulation signal imposed by said modulator and a second part operatively connected to said demodulator, said reference connected via said auxiliary connector comprising a means for ensuring that said demodulator maintains synchronism with said modulator in use of said inductive coupler.   
     
     
       2. The inductive coupler of claim 1, wherein said modulator modulates said output of said high frequency oscillator at a frequency equal to that of said power supply fed to said input of said rectifier. 
     
     
       3. The inductive coupler of claim 1, wherein said modulator modulates said output of said high frequency oscillator at a frequency double that of said power supply fed to said rectifier. 
     
     
       4. The inductive coupler of claim 2, wherein said output of said demodulator is at said same frequency as said power supply fed to said inductive coupler. 
     
     
       5. The inductive coupler of claim 3, wherein said output of said demodulator is at said same frequency as said power supply fed to said inductive coupler. 
     
     
       6. The inductive coupler of claim 1, wherein said modulation of said high frequency signal output by said modulator is an amplitude modulation. 
     
     
       7. The inductive coupler of claim 1, wherein said. modulation of said high frequency signal output by said modulator is a frequency modulation. 
     
     
       8. The inductive coupler of claim 1, wherein said modulation of said high frequency signal output by said modulator is a pulse width modulation. 
     
     
       9. The inductive coupler of claim 1 including a housing having a first part and a second part, said rectifier, said high frequency oscillator, said modulator, said primary side of said split transformer and said first part of said auxiliary coupling being contained in said first part of said housing and said secondary part of said split transformer means, said second part of said auxiliary coupling and said demodulator being contained in said second part of said housing.